/**
 * #      965
 * 名称   单值二叉树
 * 链接   https://leetcode-cn.com/problems/univalued-binary-tree
 * 题解   [304](https://leetcode-cn.com/problems/univalued-binary-tree/solution)
 * 通过率 68.7%
 * 难道   简单
 */

